If you want to allow your members to communicate with each other with the private messaging option, you need to enable this option for them to do that.

You can update these settings from your Admin Panel. In the Social Network module, click "Settings" and then "Messaging".

If you click on "People can send messages to each other.", then you will allow your members to do that.

Please note that each person can still disable getting messages from others in their profile settings.

Members can use the little inbox icon on the left side of their profile picture, to use the Messaging function.

After clicking on "Send New Message", members can choose the member(s) they want to communicate with and share their message(s) with them. Members can send their messages to more than one member.

When members receive a new message, they can see the message notification on the inbox icon. Members can also see and search all your new and previous messages on the left-side search bar.